What Do Caterpillar Eggs Look Like? A Quick Visual Guide

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Caterpillar eggs are tiny and often overlooked, but they can be quite fascinating. They come in a variety of shapes, sizes, and colors depending on the species of butterfly or moth they belong to. Some eggs may appear round and smooth, while others could be oval and textured. Paying attention to these unique details can help you identify which caterpillar species will emerge from the eggs.

As you explore nature, you might notice caterpillar eggs laid on leaves, stems, or other suitable surfaces. They are usually found on or near the host plants that caterpillars feed on after hatching. The eggs may be laid individually or in clusters, depending on the butterfly or moth species. For example, the redhumped caterpillar lays its eggs in groups on host foliage.

Being able to recognize caterpillar eggs and their distinctive characteristics can be a valuable skill for gardeners, nature enthusiasts, or anyone interested in the life cycle of butterflies and moths. It can also help protect your plants from potential damage caused by caterpillars, as you’ll be able to spot their eggs before they hatch and take any necessary preventative measures.

General Appearance of Caterpillar Eggs

Color Spectrum

Caterpillar eggs come in a variety of colors, depending on the species. Common colors include shades of:

  • Red
  • Yellow
  • White
  • Green
  • Off-white

It’s important to note that colors can change as the eggs mature, which may make them more difficult to identify.

Size and Shape

Caterpillar eggs are usually small and round, although their size and shape can differ between species. Here are some examples:

  • Eggs of some species may be as small as a pinhead.
  • Others might be slightly larger, around the size of a sesame seed.


Caterpillar eggs can have different textures, too. For instance:

  • Some eggs might have a smooth surface.
  • Others may appear granular or rough.

Inspecting the eggs closely can help you determine their texture.

Seasonal Variation

The appearance of caterpillar eggs can vary by season. Generally:

  • Some species lay their eggs in early spring, as the weather starts to warm up.
  • Others may wait until summer or even fall, depending on their specific lifecycle and environmental requirements.

Keeping an eye on seasonal changes can help you spot and identify caterpillar eggs more easily.

Specific Species of Caterpillar Eggs

Monarch Butterfly Eggs

Monarch butterfly eggs are tiny, oval-shaped, and have a cream color. They are usually laid singly on a milkweed plant leaf, which serves as their food source. A noticeable characteristic includes raised ridges running vertically up their surface.

Example features:

  • Tiny (1mm in size)
  • Oval shape
  • Cream color
  • Single eggs on milkweed leaves

Black Swallowtail Butterfly Eggs

Black swallowtail butterfly eggs are light-green and spherical, found singly or in small groups on a variety of host plants such as parsley, dill, and carrot tops. They appear smooth and shiny, typically measuring around 1mm in diameter.

Example features:

  • Spherical shape
  • Light-green color
  • Single eggs or groups
  • Host plants: parsley, dill, and carrot tops

Pipevine Swallowtail Butterfly Eggs

Pipevine swallowtail butterfly eggs are small, reddish-brown, and spherical. They are often laid in clusters on the undersides of pipevine plant leaves, which serve as their only food source.

Example features:

  • Spherical shape
  • Reddish-brown color
  • Clustered on pipevine leaves

Zebra Longwing Butterfly Eggs

Zebra longwing butterfly eggs are small, light-yellow, and barrel-shaped. They are laid individually on passionflower vine leaves, with several eggs spread across the plant to ensure survival.

Example features:

  • Barrel-shaped
  • Light-yellow color
  • Individually laid on passionflower vines

Brimstone Butterfly Eggs

Brimstone butterfly eggs are tiny, about 1mm in size, and resemble a greenish-yellow, truncated cone. They are laid singly on the leaves of buckthorn or alder buckthorn plants, which act as their primary food source.

Example features:

  • Greenish-yellow color
  • Tiny, cone-shaped (1mm in size)
  • Single eggs on buckthorn plants

Gulf Fritillary Butterfly Eggs

Gulf fritillary butterfly eggs are pale-yellow and elongated, with several small ridges at the top. They are laid singly on the leaves of passionflower vine, which serves as their food source.

Example features:

  • Pale-yellow color
  • Elongated with ridges
  • Single eggs on passionflower vines

Eastern Black Swallowtail Butterfly Eggs

Eastern black swallowtail butterfly eggs are cream-colored and spherical, measuring approximately 1mm in diameter. They are laid singly on an array of host plants, including dill, parsley, and fennel.

Example features:

  • Cream color
  • Spherical shape (1mm in diameter)
  • Single eggs on dill, parsley, and fennel plants

Life Cycle of a Butterfly

Laying of Eggs

During the first stage of the butterfly life cycle, a female butterfly will oviposit, or lay tiny, cream-colored eggs, usually on the underside of a leaf. For example, monarch butterflies lay their eggs on milkweed plants. The choice of plant is crucial, as it serves as a food source for the hatching caterpillars.

Hatching of Larva

In about 4 days, the eggs hatch into worm-like larvae, also known as caterpillars. Upon hatching, the caterpillar’s main goal is to eat and grow. During this stage, they will molt multiple times, allowing them to increase in size.

Metamorphosis Into Pupa

When the caterpillar has reached its maximum size, it enters the pupa stage. The caterpillar forms a protective shell, called a chrysalis, around itself. Inside the chrysalis, the larva undergoes a transformation, or metamorphosis, into an adult butterfly.

Adult Butterfly Stage

After several days to a few weeks, the fully-formed adult butterfly emerges from the chrysalis. The adult butterfly has a new set of wings and is ready to reproduce, starting the life cycle all over again.

During each stage of the life cycle, butterflies undergo various transformations:

  • Egg: A tiny, cream-colored, and usually oval-shaped structure
  • Larva: A caterpillar, which feeds on its host plant
  • Pupa: A chrysalis, in which the caterpillar metamorphoses into a butterfly
  • Adult: A fully-formed, winged, and reproductive insect

By understanding the life cycle of a butterfly, you can appreciate the remarkable process these creatures go through to become the colorful and graceful insects we know and love.

Habitation and Host Plants

Common Habitats

Caterpillars can thrive in a variety of habitats, but they are commonly found in gardens, meadows, and forests. In these areas, they seek out host plants that provide the nutrition they need for growth. Several host plants are commonly available in gardens and meadows, making them ideal habitats for caterpillars.

Host Plant Preferences

Caterpillars have specific host plant preferences, depending on their species and the plants available in their environment. Some of the most common host plants caterpillars consume include:

  • Milkweed plants: These plants are a popular choice for Monarch butterflies and caterpillars. The leaves provide essential nourishment, and Monarchs lay their eggs on milkweed plants.
  • Parsley, fennel, and dill: Caterpillars from different species enjoy feeding on these plants, which are commonly found in gardens and meadows. These plants not only attract caterpillars but also enrich your garden with their lovely scents and decorative foliage.
  • Carrot and hop: Some caterpillar species find their nourishment in the leaves of these plants, making them essential host plants in their habitats.

By understanding caterpillar habitats and host plant preferences, you can support these fascinating creatures in their lifecycle and witness the beauty they bring to your surroundings.

Importance and Impact of Caterpillar Eggs

Role in Ecosystem

Caterpillar eggs play a crucial role in the ecosystem as they serve as food for various predators, like birds and insects. Additionally, when caterpillars hatch from these eggs, they contribute to the ecosystem by feeding on plants and converting it into energy for their growth and development. This process also helps in maintaining the population of plant species like aspen, birch, oak, linden, and ash.

For example, monarch caterpillars specifically feed on milkweed plants and indirectly assist in controlling the growth of this plant. Caterpillars also provide benefits to the ecosystem by becoming a food source themselves for their predators upon reaching the larva stage.

Significance in Gardening

Caterpillars, such as the larvae of butterflies and moths, can have both positive and negative impacts on gardening. On one hand, they are essential to the lifecycle of some beautiful species of butterflies and moths. However, their voracious appetites can sometimes cause damage to plants and crops. For instance, redhumped caterpillars can feed on the leaves of host plants while in their larva stage.

When managing caterpillars in a garden, it is essential to strike a balance between supporting pollinators and preventing significant damage. In some cases, natural predators like birds and insects can help control caterpillar populations. However, if an infestation occurs, gardeners may need to consider using targeted organic pesticides to protect their plants.

Here are some pros and cons of caterpillars in gardening:


  • Provide a food source for birds and insects.
  • Contribute to the lifecycle of beautiful butterfly and moth species.
  • Can help control certain plants’ growth by feeding on them.


  • Can cause significant damage to plants and crops.
  • May require the use of targeted pesticides to control infestations.

By understanding the importance and impact of caterpillar eggs in the ecosystem and gardening, you can make informed choices about how to manage these fascinating creatures in your own yard or garden. Just remember to consider their role in supporting biodiversity and weigh the pros and cons before taking any action.


  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

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  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

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Tags: Caterpillars

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7 Comments. Leave new

  • I also found those tiny blue eggs on my dill weed. They hatched into tiny inch (millimetre) worms, too. JL Prince Rupert, BC Canada I posted an image of the eggs and worms on BugGuide.net ID request. No one has ID them yet, so thanks for this.

  • Found 14 greenish eggs on a vine that the long tail skipper likes. There were 6 on each straight line and another 6 in straight line. At the tip and bottom was one egg on tip and one on bottom. Wondering what it could be. The eggs after a wk. are turning clear transparent.

  • Hi,
    Just at the school I went there was a dead mother oakworm moth with many eggs on her. I tried to place these on the tree but most did not stick so I brought them back in a container. My question is: If the eggs fall near an oak tree will they do fine or do they need to be stuck on the oak leaf? I would think they would be ok but I am not sure. thank you

    • They would stand a better chance if the female laid the eggs on the actual food source.

  • Hi,
    Just at the school I went there was a dead mother oakworm moth with many eggs on her. I tried to place these on the tree but most did not stick so I brought them back in a container. My question is: If the eggs fall near an oak tree will they do fine or do they need to be stuck on the oak leaf? I would think they would be ok but I am not sure. thank you

  • Today is August 14th 2021.
    We had put up very fine bird netting over our outdoor chicken coop and these eggs have been layed all over it I tried spraying it with the hose to remove them with no luck. I guess the lucky part will be when they hatch, our chickens and ducks will have a feeding frenzy.


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